That 2013 Bali Advertiser article rambles on repeating the gossip you can get all over the place, but does not add any real info. Almost worthless.
PDAMs (Perusahaan Daerah Air Minum) or water supply authorities are fairly local, maybe at the Regency level, or maybe even more local. They do sometimes add chlorine - I lived in a house in Kaliasem, Lovina that use PDAM water and it had so much chlorine at times that you would not use it to make a cup of tea.
Often your water supply, whether PDAM or a local bore will give water that is safe to drink - but the problem is - not always - and there are no guarantees, no regular testing, so it's "drinker beware". A well that is normally OK, may become contaminated after heavy rain that causes nearby septic tanks to overflow and contaminate your aquifer.
So you can buy Aqua gallons or similar on the assumption that they do regular testing. I don't know that they do - but guess that it is likely.
Or you can filter using setups available from Kopernik (see
https://www.kopernik.ngo/) or similar. They use ceramic filters that have small enough holes to keep out almost all the bacteria that could give you gut problems. They also incorporate silver compounds aimed at killing bacteria, and activated carbon aimed at removing stinky contaminants etc. There is enough info to suggest these work fairly well with reasonably clean water sources, but again no guarantees - you need to have faith. There is very little info on how often you should clean these to get rid of bacteria blocked on the inpput side, and not much info on how often to replace as the silver and activated carbon parts get used up.
Kangen water (or ionized alkaline water) has a strong following in Indonesia for its supposed health benefits. There are machines to produce it from tap water, and the process in different. There is no attempt to filter out the bacteria.
